Air-cooled engine



Jan. 25, 1955 R,vc. cHEsNUTT Awcgonn ENGINE --3 .,Shaqts-Sheet l Filed Oct. 14. 1950 "www Jan. 25, 1955 Filed Oct. 14. 1950 R. c. cHEsNu'rT' 2,700,377

AIR-coman ENGINE 3 Sheets-Sheet 2 INVENTQR RALPH C. CHESNUTT ATFORNEY Jan. 25, 1955 R. c. cHEsNuTT AIR-0001.213 ENGINE 5 Sheets-Sheet 3 Filed Oct. 14. 1950 .Zi/j@ c. w ss A@ fu/U A Tra/2HE f5 United States Patent O AIR-COOLED ENGINE Ralph C. Chesnutt, Cleveland, Ohio Application October 14, 1950, SerialNo. 190,198

6 Claims. (Cl. 12S-41.65)

This invention relates to an internal combustion engine, and more particularly to such an engine which is designed to be air cooled.

An object of the invention is to obtain improved and adequate cooling of the intake and exhaust valves of an internal combustion engine.

Another object is to obtain improved and adequate cooling of the combustion chamber and spark plugs.

Another object is to obtain an improved air cooled internal combustion engine which may be operated at a high compression ratio and which will yield high thermal eiliciency and power output.

Another object is to obtain an improved internal combustion engine in which improved lubrication takes place.

Other objectswill hereinafter appear:

.Figure 1 is a view, partially inend elevation and partially in section, of an internal combustion engine embodying my invention.

Figure 2 is a fragmentary side elevational view of one end of the engine of Figure 1,

Figure 3 is a fragmentary plan sectional view, parts being shown in section taken on the line III- III of Figure l.

The engine shown includes a crankcase 1 within which is journaled the crank-shaft, the bottom of the crankcase being closed by a cover or pan 3.

Secured to the top of the crank-case, as by machine screws, are the cylinders which are shown as cast in pairs, the illustrated casting comprising one pair being indicated in general by 5.

To the top of the cylinder casting is secured a cylinder head casting 6, also constituting parts of the pair of cylinders defined by casting 5.

Within the cylinder casting 5 are the pistons 7, each provided with a plurality of rings 8 and connected by a Wrist pin 9 to a connecting rod 10, the lower end of which is connected to the crank-shaft 2.

The cylinder head 6 is formed with a Siamesed intake port 11, and beyond this with two outlet ports 12, and in these, respectively, are mounted the intake valves 13 and the exhaust valves 14, these being of the valve-inhead type with upwardly extending stems 15 normally urged upwardly to closed position by springs 16 engaging abutments 17 secured to the valve stems near their upper ends, the valves being actuated by rocker arms 18, pivoted at 19 and rocked by rods 20 which are actuated from the cam shaft 21 located in the crank-case.

It will be noted that while the heads of two cylinders are formed as a single casting, the wall 11a, which encloses the two intake ports 11, is spaced from both walls 12a and 12b, which encloses the exhaust ports 12, so that passages for air between the intake and exhaust valve enclosures are provided.

These passages are spanned by tins 22, and similar tins 23 are provided on the exterior of the cylinder casting 5.

A series of open spaces between these ns are formed between each of the two cylinders of a casting block 5.

The valve rods extend upwardly within the cylinder casing in cored vertical tubular reces/ses 25, while, in passing through the cylinder head, they 'are shrouded by short lengths of tubing 26 extending between the upper and lower flanges of the cylinder head and secured thereto as by being anged and gasketed at their upper ends and threaded at their lower ends into the lower flange.

A casing 27 encloses all rocker arm mechanism and is provided with threaded breather plug 28 threaded into "ice i an aperture through its top. Wing nuts 29 are shown securing this cover to the bracket 30 which carries the pivot pins 19.

A timer or distributor for ignition current is indicated at 31, and a carburetor at 32, while a starter and generator are indicated at 34 and 33 respectively, but these four parts being of any known or' desired construction, and not constituting per se a part of the present invention, need not be described in further detail.

From the carburetor, an intake manifold 35 extends upwardly and is branched to connect with the intake ports 36 of each of the cylinder blocks, while branches 37 of an exhaust manifold communicate with eachof the exhaust ports 38.

Carried at one end of the crank-case is a centrifugal blower, consisting of a rotor 39 xed to the end of the crank-shaft as by nut 40 and a generally circular casing 41 having an excentric discharge portion 42.

The discharge from the blower opens into a space shown at the carburetor side of the cylinder blocks and defined by a shroud consisting of a lower part 43 and a detachable cover 44 held in .place by machine screws 45.

Thus it will be seen the shroud provides a relatively large discharge space for the blower, which space extends along one side (shown as the carburetor side) of all of the cylinder blocks, and that air supplied to the space by the blower must travel from it transversely of the engine through the spaces between successive cylinder blocks, and also the spaces between the successive cylinders of each block, as well as through the spaces between walls 11a, 12a and 12b, thus thoroughly sweeping over the tins 22 and 23 and traveling at high velocity where. it passes between cylinder and parts of cylinder head. In this manner excess heat is eiectively` carried away as by convection. A vertical wall of the shroud is provided with a tting communicating blower air from within the shroud through the conduit 48 to the thermostat casing 49. This wall of the shroud has an inturned portion 6U which lies close to the end of the cylinder block.

Spark plugs 46 are located in threaded bosses 47, shown as positioned between tubes 26.

A tube 48 is connected to the housing of a thermostat 49, which in turn communicates with the interior crankcase. The other end of tube 48 is connected with the pressure side of the blower 41 and so permits air from the blower to be driven into the crank-case in quantities determined by the temperature. Naturally, when the motor is cool the thermostat closes or nearly closes the passageway for the air, and as the temperature rises opens this passageway to permit more cool air to be supplied to the crank-case. This causes air from the crank-case to ilow upwardly through the passages 25 and tubes 26 to the space or chamber within the housing 27.

This housing is, of course, electively cooled by impingement upon it of cooling air from the blower.

It will be noted also that not only does the cooling air sweep effectively between the cylinder and valve enclosure but that this air impinges directly on the spark plugs and maintains these likewise in properly cooled condition.

The small stream of air entering the crank-case serves to cool the crank-case itself and the parts and oil therein. In as much as air cooled engines run hotter than those which are water cooled, the cooling of the crank-case is a distinct advantage. Of course, the customary crankcase breather (not shown) is also used.

It will be noted that the generator, starting motor, timer, and carburetor are all outside of the shrouded portion of the engine, in places where they are not exposed to excessive heat.

The major portion of the intake manifold, including the upper inlet from the carburetor, the distributing horizontal portion and the branches to the cylinder casting, is all included within the cover or shroud so that these parts are exposed to heat radiating from the cylinder blocks and thus warm the incoming combustible mixture of fuel and air.

While I have described the illustrated embodiments of my invention in some particularity, others will readily' occur to those skilled in the art to which it appertains;

and I do not, therefore, limit myself to the precise details.`

shown andldeseribed herein, but claim as my invention all variations, modications, and embodiments thereof coming within the scope of the appended claims.

I claim:

1. An internal, combustion engine of the valve-in-head type-having valve voperating push rods extending from the crankcaseto4 the cylinder head, a closure secured ,to the cylinder head enclosing the valve mechanism thereon, 'the push rods being enclosed in conduit means `spaced therefrom and extending from the crank-case to the closure, andblower'means blowing air into thecrank-case.

2. An internal combustion engine of the val-ve-in-head type having Valve operatingpush rods extending from the crankcase to the cylinderhead, a closure secured to the cylinder head enclosing the valve mechanism thereon, the pushl rodsbeing enclosed in conduit means spaced therefrom and extendingfrom the crankcase to ,the closure, blower Aineans4 blowing air into the crankease, .and `athermostat controlling the flow of the air.

` 3. An air-cooled internal combustion engine of the valve-in-head type having Valve operated push rods extending from thecrank case to the cylinder head, a closure secured to the cylinderhead enclosing the valve mechan'ism thereon, push rods actuating said valve mechanism, conduit means in said cylinder head for receiving each of said push rods, said push rods being spaced fromV the walls of said conduit means, and blower means blowing air into said crankcase, and means conveying air from the crankcase tothe conduit means. 4. In an air-cooled internal combustion engine ofthe v-a'lve-in-hea'd type including a crankcase, a cylinder block and blower means'blowing air vinto the crank case, a cylinder head having spaced apart upper and lower walls extending outwardly therefrom and provided with aligned openings, conduit means connecting said aligned openings and adapted to receive push rodsin spaced relation to the walls of the conduit means, said conduit means having connection with blower airfrom said crank case.

In anar-cooled internal combustion engine of the valve-in-head type including a crank case, a cylinder block and blower means blowing air into the crank case, a cylinder head having spaced apart upper and lower walls extending outwardly therefrom and provided with aligned openings, tubes connecting each of said aligned openings for receiving push rods in spaced relation thereto, and conduit means communicating blower air from the crankcase to the said push rod tubes.

6. In an air-cooled internal combustion engine of the valVe-in-head type includinga crankcase, a cylinder block and blower means blowing air into the crankcase, a cylinder head hzwrnglspaced apart. upper` and lower walls extending outwardly therefrom and provided with aligned openings, -tubes connecting each of said aligned-openings for receiving pushrodsin spaced relation thereto, and conduit means communicating blower air from the crankcase to the said push rod tubes, said tubes being secured at their respective terminal ends to the walls of the aligned upper and lower cylinder `head openings.

References" Cited vin the'le of this,l patent v UNITED .STATES VPAIENTS 1,087,259 De Richelle Fe'b. 17, 1914 1,396,418 vGilliard Novg, 1921 l1,408,179 DuPont 'Feb.'28, 1922 1,409,822 "Brock 'Mar. 14, 1922 1,783,085 Halford Nov. ,25,1930 1,785,108 Bastien "Dec.`16,'l`930 1,838,436 Morrill Dec. j29, l1931 1,930,508 ,Conant Oct. 17, "1933 1,968,119 Barker July 31, 1934 -2,029,216 Barker Jan. 28, 1936 `2,089,454 Walden Aug. l0, 1937 2,252,974 Lowther Aug. 19, 1941 2,253,505 Cantoni ,Aug.,.26, 1941 FOREIGN PATENTS 874,346

France of 1942 

